The reliability of fuel cell systems, such as a solid oxide fuel cell (SOFC) system, greatly depends on the presence and concentration of undesirable constituents in the fuel stream. Undesirable constituents, such as moisture, oxygen, siloxanes, and sulfur (including sulfur compounds), may degrade the fuel cell stack's performance and cause irreversible damage resulting in decrease efficiencies and costly replacement. Specifically, when using natural gas as a fuel, fuel cell systems require gas purification to remove, for example, sulfur and sulfur compounds, siloxanes, moisture, etc. Passing fuel through sorbent beds is one way to purify the natural gas from fuel prior to use in a fuel cell. However, sorbent beds (e.g., desulfurization adsorption beds) have a finite life and once the sorbent bed is exhausted, sulfur may pass through the sorbent bed without being absorbed and reach the fuel cell stack causing permanent damage. Even if sorbent beds are replaced prior to exhaustion, there may be underutilized portions of the sorbent bed increasing the cost of sorbent bed replacement. Additionally, other undesirable constituents not filtered by the gas purification sorbent beds may cause damage to the fuel cell stack shortening its operational life.